In the accompanying diagram, three vertices of parallelogram ORST are O(0,0), R(b,d), and T(a,0). What are the coordinates of S?A. (a, b)B. (a+b, d)C. (a+b, b)D. (a, d)

In a parallelogram, the opposite sides are parallel.
This means that RS is parallel to OT. So, the y value of S is the same as the y value of R, which is d, so y = d. Thus:
[tex]S=(x,y)=(x,d)[/tex]Now, we need to find x.
Since the sides RO and ST are also parallel, the x distance from O to R is the same as the x distance from T to S.
The x distance from O to R is
[tex]b-0=b[/tex]The x distance from T to S is
[tex]x-a[/tex]Since these x distances are equal, then:
[tex]\begin{gathered} b=x-a \\ x=a+b \end{gathered}[/tex]Then, the coordinates of S are:
[tex](a+b,d)[/tex]Which corresponds to option B.